Question

J. The Bk-249 has a half-life of 320. days, decays by beta emission, and also

emits gamma rays. Determine the fraction of Bk-249 that remains unchanged
after 960. days.

K. State, in terms of both protons and neutrons, why Uus-293 and Uus-294 are
isotopes of the same element..

Answer 1

J. Since the half life is 320 days, divide 960 by 320 to get 3 half lives. So over 960 days, the mass of Bk-249 will be halved 3 times:

One half life (1/2), two half lives (1/4), three half lives (1/8). Answer: 1/8

K. Uus-293 and Uus-294 are the same element since they both have 117 protons. They are isotopes because they have a different number of neutrons, Uus-293 has 176 neutrons (293-117) and Uus-294 has 177 neutrons (294-117).